Recently, object recognition devices have become practical that detect another vehicle approaching an own-vehicle from a side of the own-vehicle, by means of millimeter wave radars installed in the own-vehicle, and that determine whether there is a risk of collision between the own-vehicle and the other vehicle.
Meanwhile, such existing mass-produced object recognition devices determine, when they detect a target-object by means of millimeter wave radars mounted on the own-vehicle, a risk of collision based on positional coordinate information which regards the target-object as a point. Therefore, the object recognition devices cannot determine the size of the target-object.
That is, in a case where a radar has detected an object, an object recognition device determines a possibility of collision based on the position coordinates of a point, on the object, that the radar has captured (captured point). Accordingly, even when there is a risk of collision between the object and the own-vehicle, it may be determined that the risk of collision between the own-vehicle and the object is low, depending on the position of the captured point on the detected object. A more specific description will be given below with reference to FIG. 14.
FIG. 14 shows a case where another vehicle VO is approaching an own-vehicle VM from the forward-left direction. With reference to FIG. 14, it is assumed that, for example, in a case where the own-vehicle VM is at an A1 point, a radar installed in the own-vehicle VM has detected a right front edge of the other vehicle VO which is at a B1 point (a tip of the other vehicle VO nearest to the own-vehicle VM), as a captured point P. Then, when the own-vehicle VM advances to an A2 point and the other vehicle VO advances to a B2 point, if the positional relationship between the captured point P and the own-vehicle VM alone is taken into consideration, it is considered that the own-vehicle VM does not collide with the other vehicle VO and they can pass by each other. However, if the size (length) of the other vehicle VO is taken into consideration, it is highly possible for the own-vehicle VM to collide with the other vehicle VO actually, as shown in FIG. 14. That is, a general object recognition device regards the target as a point and does not take the size of the target into consideration, and thus the case shown in FIG. 14 may occur.
A technology for solving such a problem is, for example, a device disclosed in Patent Literature 1. The device disclosed in Patent Literature 1 searches, when a radar has detected a target-object, an area around the detected point by means of a camera, and detects an edge of the target-object.    [Patent Literature 1] Japanese Patent Laid-open Publication No. 2007-279892